A dad in northern California is definitely in the running for father in the year, for building, a rollercoaster in his yard, for his little boy. This one, we had to see for ourselves. So, ABC's nick watt went to check it out. ? Reporter: Will makes every other dad in the world look bad. Bam. Lyle asked me to build a backyard rollercoaster. And I said, yes. Best dad ever. Reporter: It's hand-powered. Three, two, one. Reporter: Is it safe? Depends on what you mean by safe. I'm just kidding. It is safe. We've had only one incident on it so far. Will is responsible. He studied aeronautics in college. But he's not a professional here. It took him 300 hours to build and $3,500 in materials. When we built it, she was happy. Reporter: This is now a thing, the backyard rollercoaster. There are others on the internet. But none as fancy as will's. Maybe he is the best dad ever. For "Good morning America," nick watt, ABC news, Los Angeles. I asked for a deck. He won't be best dad until he goes, depends on what you mean. So far, soo good. Coming up, Angelina Jolie on marriage and movies.

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California Dad Builds Backyard Roller Coaster

Will Pemble's son, Lyle, 10, took test rides during phase 1 of construction in 2013.

Deadly Accident on Texas Roller Coaster

Woman falls to her death on 'Texas Giant' roller coaster ride at Six Flags amusement park.

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